Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermodynamic and Structural Properties of Polystyrene-Polybutadiene-Polystyrene Block CopolymersE. Campos-Lopez, D. McIntyre, and L. J. FettersCite this: Macromolecules 1973, 6, 3, 415–423Publication Date (Print):May 1, 1973Publication History Published online1 May 2002Publ…
The application of the typical metallic refractory compound lanthanum hexaboride as a thin-film material has been studied. Film properties are estimated by using bulk optical constants derived from a Kramers-Kronig analysis of the bulk material. Films with thicknesses of 130–2000 Å have been prepared by sputtering and…
Continuum theory is used to calculate the molecular alignment and the elastic deformation energy in a nematic layer containing a circular-loop thread. In agreement with experiment, planar solutions are found, with the thread being the boundary between regions of different pitch. It is shown that threads in nematics an…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMatrix Raman spectrum of the fluorine molecular anion, F2-Wilmont F. Howard and Lester. AndrewsCite this: J. Am. Chem. Soc. 1973, 95, 9, 3045–3046Publication Date (Print):May 1, 1973Publication History Published online1 May 2002Published inissue 1 May 1973https://doi.org/10.…
Abstract Methyl methacrylate has been continuously polymerized in toluene solution with AIBN as an initiator at 60°C in a jacketed steel vessel of 890 ml volume with holding times of several hours. Provision was made for good mixing and introduction of a steady stream of monomer, solvent, and initiator. The effluent s…
During the fracture of highly oriented drawn films and fibers of crystalline polymers, one observes a great many radicals produced by chain rupture. The description of such material by the logarithm of the time to break under applied load as a linear function of stress with the activation energy of the covalent bond s…
Using the transition probabilities obtained by the method of the previous paper I, efficiencies of several infrared-to-visible conversion processes, as well as rates for resonance energy transfer and cooperative optical transition, are calculated and compared with experiments. Agreement seems to be satisfactory if the…
Abstract Linear thermal expansions of eleven alkali halides have been determined at room temperature, from 90 to 54 K, and from 30 to 1.5 K. Values are given for the Grüneisen parameter γ = 3αV / Cx, where α is the linear expansion coefficient, C / V the heat capacity per unit volume, and X is the compressibility. For…
Abstract Heat capacities of molten polyethylene, polypropylene, poly‐1‐butene, polystyrene, and poly(methyl methacrylate) were measured over a wide range of temperature by using a differential scanning calorimeter. The upper limit of temperature was established for each polymer at about 10°K below the beginning of the…
Estimations are made of the critical concentration of energy-acceptor ions for which the average efficiency of the excitation transfer from energy-donor ions is 1/2. This gives a measure of the activator concentration at which Inokuti and Hirayama's theory is no longer applicable. Study is also made of the dominant mu…
The optical constants nx, kx, nz, and kz of the uniaxial compound GaSe have been determined in the energy region 2–5 eV (wavelength region 240–700 nm) using ellipsometric measurements on a plane perdendicular to the optic axis (the cleavage plane) and a plane parallel to this axis.
Abstract A mineral with a 10Å X‐ray spacing is the dominant clay mineral in the surface horizon of many dryland soils in which vermiculite or vermiculite‐biotite is dominant in subjacent horizons. The mineral occurs in soils with aridic, torric, xeric, and ustic moisture regimes. To study its genesis we separated weat…
DC conductivity measurements were carried out on low-density polyethylene films of thickness 25, 50 and 75 μm. The material showed non-ohmic conduction on application of high electric fields in the range 1 × 10 7 to 3 × 10 7 Vm −1 . The results were applied to a model proposed by Adachi et al (1971) and good agreement…
A measurement is presented of the anisotropic liquid-structure factor of $p\ensuremath{-}n$-octyloxybenzylidene-${p}^{\ensuremath{'}}$-toluidine in the nematic phase using monochromatic Cu $K\ensuremath{\alpha}$ radiation. This material has a smectic $A$ phase at lower temperature and exhibits strong pretransition sca…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAzodicarboxylic acid esters as dealkylating agentsEdward E. Smissman and Alexandros MakriyannisCite this: J. Org. Chem. 1973, 38, 9, 1652–1657Publication Date (Print):May 1, 1973Publication History Published online1 May 2002Published inissue 1 May 1973https://pubs.acs.org/do…
Abstract Unter den Metallchelaten des Phthalocyanins (Me‐Pc), des polymeren Phthalocyanins und des Tetraazaannulens (Me‐TAA) mit Me = H, Fe, Co, Ni und Cu befinden sich Vertreter hoher Aktivitä bezüglich einer Elektrokatalyse der Sauerstoffreduktion. Aus voltammetrischen Messungen an den in 85‐96% Schwefelsäure gelöst…
Abstract Needle‐like crystals of polyoxymethylene, 5 to 20 μm long, have been obtained in the course of the polymerisation of trioxane in cyclohexane. It has been found that such crystal growth is favoured at large BF 3 .OEt 2 /H 2 O or BF 3 /H 2 O ratios, when the nucleation takes place fast. The needle is considered…
Denaturation temperature of pepsin-treated collagen from calf skin was measured Viscometrically in neutral pH solution by adding glucose which completely depresses collagen fibril formation without denaturing collagen molecules. The stability of collagen molecules in solution thus obtained was greater at neutralpH tha…
As a part of the research program on the behavior of polluted insulators, the mechanism of flashover due to contamination has been analysed in a recent publication [1].
Two sets of skinfold measurements were made on 21 subjects by three observers using a Harpenden caliper. One of the observers had several years’ experience of the technique, while the other two were relatively inexperienced. Measurements were made at the biceps, triceps, subscapular and suprailiac sites. In one set o…